A signal demodulation-based method for the early detection of Cheyne-Stokes respiration.

Cheyne-Stokes respiration (CSR) is a sleep-disordered breathing characterized by recurrent central apneas alternating with hyperventilation exhibiting a crescendo-decrescendo pattern of tidal volume. This respiration is reported in patients with heart failure, stroke or damage in respiratory centers. It increases mortality for patients with severe heart failure as it has adverse impacts on the cardiac function. Early stage of CSR, also called periodic breathing, is often undiagnosed as it only provokes hypopneas instead of apneas, which are much more difficult to detect. This paper demonstrates the proof of concept of a new method devoted to the early detection of CSR. The proposed approach relies on a signal demodulation technique applied to ventilation signals measured on 15 patients with chronic heart failure whose respiration goes from normal to severe CSR. Based on a modulation index and its instantaneous frequency, oscillation zones are detected and classified into three categories: CSR, periodic breathing and no abnormal pattern. The modulation index is used as an efficient indicator to quantify the degree of certainty of the pathology for each patient. Results show high correlation with experts' annotations with sensitivity and specificity values of 87.1% and 89.8% respectively. A final decision leads to a classification which is confirmed by the experts' conclusions.

Three related cases of cutaneous anthrax in France: clinical and laboratory aspects.

Anthrax is an acute bacterial infection caused by Bacillus anthracis. The infection is cutaneous in about 95% of human cases and respiratory in about 5%. Approximately 2000 cases of cutaneous anthrax are reported annually worldwide. This disease became exceptional in Europe thanks to strict veterinarian monitoring. The last human cases of anthrax indicated in France were in 1997. We report 3 new related cases of naturally acquired cutaneous anthrax that occurred in France in 2008. The unique features of these cases include the atypical clinical presentation and the contribution of the rapid and specific diagnosis techniques by polymerase chain reaction.In cutaneous forms of anthrax, although the local course is not influenced by the treatment, antibiotic therapy is necessary to control any bacterial distribution. A case of exposure similar to that of a confirmed human case or an exposure identified by epidemiologic inquiry should usually result in chemoprophylaxis. Chemoprophylaxis for the close relations of a patient or for health workers is unnecessary since person-to-person transmission has not been reported.